Glaucoma is a family of optic neuropathies which cause irreversible but potentially preventable vision loss. Vision loss in most forms of glaucoma is related to elevated intraocular pressure or “IOP” with subsequent injury to the optic nerve. Secretion of aqueous humor and regulation of its outflow are physiologically important processes for maintaining IOP in the normal range. See FIGS. 1-2.
Treatment protocols for glaucoma currently include medication, conventional surgery, and laser surgery. Each of these protocols has significant side effects, complications, and limited long-term efficacy. Side effects of medication adverse interaction with other oral medications (such as aspirin, oral beta-blockers, calcium-channel blockers, and quinidine), aggravation of asthma and other lung-disease symptoms, allergic conjunctivitis, allergic reactions, altered taste, anemia, anterior uveitis, anxiety, brow-aches, burning, cataract, ciliary spasm, conjunctival thickening, convulsions, coronary arrhythmia, crib death in infants, depression, dim vision, dry mouth, enlarged pupils, epithelial keratopathy, eye pain, fatigue, follicular conjunctivitis, frequent urination, headaches, high blood pressure, increased heart rate, increased pupillary block, IOP reduction in fellow eyes, IOP spikes (especially when switching from other glaucoma medications), iris cysts, kidney problems, lethargy, lid elevation, loss of appetite, low blood pressure, macular edema in aphakic eyes, miosis, muscle and joint pain, muscular paralysis, nearsightedness, periocular contact dermatitis, pseudomyopia, reactivation of herpes keratitis, red and itching eyes and lids, reduction in corneal sensitivity, respiratory failure, retinal detachment, sexual dysfunction, stinging, stomach problems, tearing, weight loss, conjunctival hyperemia. See European Glaucoma Society, Terminology and Guidelines for Glaucoma 127-37 (3d ed. 2008); University of Illinois Eye & Ear Infirmary, The Eye Digest, Drug Treatment for Glaucoma (2003); New York Times, Health Guide, Glaucoma, In-Depth Report: Medications (Jun. 23, 2009) (hereinafter “NYT: Medications”), avail. Mar. 10, 2012, at <http://health.nytimes.com/health/guides/disease/glaucoma/medications.html>. In addition, adherence to medication protocols can be confusing and expensive. If side effects occur, the patient must be willing either to tolerate these or communicate with the treating physician to improve the drug regimen. Poor compliance with medication protocols and follow-up visits is a major reason for vision loss in glaucoma patients. See Health Guide: A New Understanding of Glaucoma, New York Times (Jul. 15, 2009), avail. on Mar. 10, 2012, at <http://www.nytimes.com/ref/health/healthguide/esn-glaucoma-ess.html>.
Examples of conventional surgical protocols include trabeculectomy, non-penetrating deep sclerectomy or “NPDS,” canaloplasty, and glaucoma drainage implants. Complications include blister-like bumps or “blebs,” scarring, cataracts, hypotony (very low eye pressure), detached retina, breakdown of the cornea, bleeding, and eye movement disorders, such as strabismus (crossed eyes) or diplopia (double-vision). See Kent, Which Glaucoma Surgery For Which Patient?, Rev. Ophthalmol. (Jun. 11, 2010), avail. on Mar. 10, 2010, at <http://www.revophth.com/content/d/cover_focus/c/22695/>; New York Times, Health Guide, Glaucoma, In-Depth Report: Surgery (Jun. 23, 2009) (hereinafter “NYT: Surgery”), avail. on Mar. 10, 2012, at http://health.nytimes.com/health/guides/disease/glaucoma/surgery.html; Detry-Morel, et al., Comparative Safety Profile Between “Modern” Trabeculectomy and Non-Penetrating Deep Sclerectomy, 300 Bull. Soc. Belge. Ophtalmol. 43-54 (2006), abstract avail. on Mar. 10, 2012, at http://www.ncbi.nlm.nih.gov/pubmed/16903511.
Laser surgical protocols may present fewer complications than conventional surgical protocols, but they may also provide lower long-term efficacy. These protocols include laser trabeculoplasty, peripheral iridotomy, trans-scleral diode laser cycloablation or “TDC,” and laser-assisted NPDS. There are two types of laser trabeculoplasty: argon laser trabeculoplasty or “ALT” and selective laser trabeculoplasty or “SLT.” Complications from both types of laser trabeculoplasty include post-surgical IOP increases, leading in some cases to vision loss, and development of adhesive-like substances called “peripheral anterior synechiae” that cause the iris to stick to part of the cornea. In addition, the effect of both forms of laser trabeculoplasty diminishes over time. In a retrospective analysis of longer term outcomes of SLT (n=41) compared to ALT (n=154), success was defined as an IOP decrease of at least 3 mmHg without additional medication or surgery. Success rate in the SLT group at 1, 3, and 5 year follow-up time points was 68%, 46%, and 32%, respectively, while in the ALT group it was 54%, 30%, and 31%. See Juzych, et al., Comparison of Long-Term Outcomes of Selective Laser Trabeculoplasty Versus Argon Laser Trabeculoplasty in Open Angle Glaucoma, 111 Ophthalmol. 1853-59 (2004).
The most commonly reported complications from LPI include conjunctivitis, corneal abrasion, pain, bleeding, inflammation, increased IOP, failure of the iridotomy to improve the drainage angle configuration, delayed closure of the iridotomy, and corneal scarring. Gray, et al., Efficacy of Nd-YAG Laser Iridotomies in Acute Angle Closure Glaucoma, 73 Br. J. Ophthalmol. 182-85 (1989). Additional complications include aqueous misdirection, corneal decompensation, cataract development, retinal damage, and photopsias or ghost images. See Mayer, Keeping Glaucoma Laser Therapy on Target: Strategies for Avoiding and Managing the Complications Involved in Three Common Glaucoma Laser Procedures (October 2011).
TDC complications include post-surgical IOP spikes, loss of visual acuity (two lines or more), corneal decompensation, phthisis bulbi, and corneal graft rejection. See Yap-Veloso, et al., Intraocular Pressure Control After Contact Transscleral Diode Cyclophotocoagulation in Eyes with Intractable Glaucoma, 7 J. Glaucoma 319-28 (1998).
Complications from laser-assisted NPDS include choroidal detachment, corneal edema, bleb encapsulation, postoperative hyphema, shallow anterior chamber, anterior chamber inflammation, hypotonia, choroidal detachments, increased resistance to aqueous outflow through Descemet's membrane. See Klink, et al., Erbium-YAG Laser-Assisted Preparation of Deep Sclerectomy, 238 Graefe's Arch. Clin. Exp. Ophthalmol. 792-96 (2000).
A need exist for a glaucoma treatment protocol with good long-term efficacy and fewer side effects and complications